Traditionally the guide rail of a guide rail assembly has been supported and connected to a tank wall by means of guide rail holders comprising rigid pipe segments welded thereto, the pipe segments being inserted into the respective guide rail end such that the outer surface of the pipe segment abut the inner surface of the guide rail. U.S. Pat. No. 8,277,115 disclose such a rigid arrangement. However, a rigid connection of this type is impaired with several drawbacks. More specifically, the forces and bending moments that the submersible machine exerts the connection between the guide rail and the guide rail holder for, result in the guide rail ends experiencing great stress and they risk to split open due to the rigid connection. Thereto the mixer unit in operation generates pulsating forces acting on the guide rail and guide rail holders. This lead to the wall that the guide rail assembly is connected to is worn out and shredded.
US 2002/162936 disclose an alternative way of connecting two guide rails. It describes an adapter comprising a central body having squared cross section and from which body two sets of flexible members extend in the axial direction. The two sets are inserted into the end of the respective guide rail, whereby a connection of the guide rails is achieved. The flexible members entail that abutment against the inner surfaces of the guide rails is ensured. When the plant is in operation the guide rails may neither be displaced/bend in relation to each other nor in relation to the adapter, and thus also this connection is rigid and thereby impaired with the above drawbacks.